研究生学术周末学术报告

题目：Constant bandwidth ORAM with small block size using PIR operations

时间：2017-5-19 14:00

地点：计控楼523会议室

报告人：S.M. YIU  香港大学

报告人简介：YIU教授目前在信息安全、生物信息领域发表论文100+，其中Google他引次数8627次，H-指数达到了41。YIU教授是多个重要会议的主席，包括Asiacrypt 2017/ RECOMB 2017等。近五年在PVLDB\IEEE TDSC\IEEE TIFS\IEEE TOC等顶级期刊、一区SCI期刊上发表论文近二十篇，获得了2015年ESORICS会议的最佳论文奖。

Abstract：Recently, server-with-computation model has been applied in Oblivious RAM scheme to achieve constant communication (constant number of blocks). However, existing works either result in large block size O(log6N), or have some security flaws. Furthermore, a lower bound of sub-logarithmic bandwidth was given if we do not use expensive fully homomorphic operations. The question of “whether constant bandwidth with smaller block size without fully homomorphic operations is achievable” remains open. We provide an affirmative answer in this paper. We propose a constant bandwidth ORAM scheme with block size O(log3N) using only additive homomorphic operations. Our scheme is secure under the standard model. Technically, we design a non-trivial oblivious clear algorithm with very small bandwidth to improve the eviction algorithm in ORAM for which the lower bound proof does not apply. As an additional benefit, we are able to reduce the server storage due to the reduction in block size.